Mechanical ciphering unit



L. M. POTTS MECHANICAL CIPHERING UNIT April 11, 1950 10 Sheets-Sheet 1 Filed July 5, 1946 INVENTOR LOUIS M.POTTS, DECEASED MARTHA W. G. P0TTS,EXEcuTR1x BY w April 11, 1950 1.. M. POTTS 2,504,044

MECHANICAL CIPHERING ,UNIT

Filed July 5, 1946 10 Sheets-Sheet s FIG. 8

' INVENTOR LOUIS M. POTTS, DECEASED MARTHA w. c. POTTS, EXECUTRIX BY m TTORNEY L- .M. POTTS MECHANICAL CIPHERING UNIT April 11, 1950 10 Sheets-Sheet 4 Filed July 5, 1946 FIG. l0

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INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. c. POTTS, EXECUTRIX ATTORNEY April 11, 1950 M. o'r'rs MECHANICAL CIPHERING UNIT 10 Sheets-Sheet 5 Filed July 5, 1946 E .M R E Y 05 M T R N T O ETT T, IPP A M0 6w M U A on? T 7 M a B April 1 1, 1950 L. M. POTTS 2,504,044

MECHANICAL CIPHERING UNIT Filed July 5, 1946 10 Sheets-Sheet 6 FIG. I5 7 [J65 I90 :01 I [I66 "I If g gloz 1 las 213 I I INVENTOR LOUIS M. POTT$,DECEASED MARTHA W. C. POTTS, EXECUTRIX i BY Z: 2

ATTORNEY April 11, 1950 L. M. PdTTS MECHANICAL CIPHERING UNIT Filed July 5, 1946 10 Sheets-Sheet 7 INVENTOR LOUIS M. POTTS,0EcEAsE0 MARTHA W. G. POTTS,ExEcuTR|x ATTORNEY April 11, 1950 L..M. POTTS MECHANICAL CIPHERING UNIT Filed i 5' 946 10 Sheet s 8 WATTORNEY April 11, 1950 Y -rs 2,504,044

MECHANICAL CIPHERING UNIT Filed July 5, 1946 10 Sheets-Sheet 9 INVENTOR LOUIS M. POTTS, DECEASED MARTHA W. C. POTTS, EXECUTRIX ATTORNEY April 11, 1950 1;. M. POTTS MECHANICAL CIPHERING UNIT 10 Sheets-Sheet 10 Filed July 5, 1946 FIG. 25

FIG. 26

INV ENTOR LOUIS M. POTTS, DECEASED MARTHA W. C. POTTS, EXECUTRIX ATTORNEY Patented Apr. 11, 1950 UNITED STATES PATENT OFFICE MECHANICAL CIPHERING UNIT Louis M. Potts, deceased, late of Evanston, 111., by Martha W. C. Potts, executrix, Evanston, 111., assignor to Teletype Corporation, Chicago, Ill., a corporation of Delaware Application July 5, 1946, Serial No. 681,444

7 Claims. 1

This invention relates to secret printing telegraph systems and particularly to mechanical ciphering units for accomplishing the enciphering and deciphering of telegraph messages.

A chief object of the invention is the provision of mechanical ciphering units for secret telegraph message communication.

Another object of the invention is the provision of mechanisms for use with standard printing telegraph apparatus for performing ciphering operations.

An additional object of the invention is the provision of key coding drums which afford a large number of key signal code permutations for ciphering operations without repetition.

A further object of the invention is the provision of circuit arrangements which can be conveniently used with the ciphering mechanisms in standard printing telegraph apparatus.

Other objects, features and advantages of the invention will appear as the description of the invention progresses.

One embodiment of the invention features the employment of key tape controlled coding magnets for use with a combined telegraph trans.- mitting and printing apparatus of the type disclosed in the patent of S. Morton et al., 1,904,164, dated April 18, 1933. One set of magnets is used to furnish key signal code combinations which combine with original or plain English signal code combinations to encipher outgoing signals in a transmitter of the type disclosed in the Morton et a1. patent, in which the well known Baudot start-stop system is utilized. In the type of ciphering employed in the instant invention a like condition of individual elements of the original signal code permutations and the individual elements of the key signal code permutations result in a spacing signal. On the other hand, unlike conditions of the elements result in a marking signal. For a more detailed description of such a system, reference should be had to the copending application Serial No. 462,522, filed October 19, 1942, in the name of Louis M. Potts and which issued as Patent No. 2,403,679 on July 9, 1946. The set of coding magnets used with the transmitter operate mechanical elements which combine with mechanical elements controlled from the printer keyboard to ultimately determine the position of the transmitting levers. For the printing operation a second set of coding magnets are provided which control mechanical elements which combine with the swords controlled from a selector magnet to ultimately determine the position of the selector vanes of the printer.

The code magnets for the transmitter and the receiver are controlled by suitable circuit arrangements. For particular use with this type of printing telegraph apparatus an additional circuit is provided whereby enciphered signals transmitted over an outgoing line are deciphered by the printer to print a plain English home record at the transmitting station and in which the same key tape is used for both enciphering and deciphering purposes.

A second form of the invention utilizes a set of key coding driuns having thirty-two positions for providing a large number of key signals, in place of a key tape for transmitting purposes and a second set of identical key coding drums having a like number of positions for receiving purposes. The mechanical coding elements are under the control of feelers which sense the code drum, allowing mechanical ciphering elements to shift to a spacing or marking position determined by the particular portion of the code drum which presents itself at a particular time, the periphery of the code drum being cut in a promiscuous manner representative of marking and spacing conditions. One stepping device is provided which steps a shaft on which the drums are mounted by means of a sleeve, in each cycle of operation. The drums are not advanced by this stepping device but a second stepping device is provided for such a purpose with a variable feeding arrangement, the amount of feed being determined by the position of a disc rotatable with the first stepping device. This disc is cut to varying depths and determines Whether the drums will remain in the same position or whether they will be advanced one or two steps. It is, of course, conceivable that additional depths could be provided in this disc to obtain a greater variety of feeding.

Rotatable with the shaft referred to above is an indicating dial, while a second indicating dial is provided which is rotatable with the code drum sleeve. The dials at a. transmitting station could be set at identical positions with dials at a receiving station by a prearrangement before the commencement of ciphering operations. code drum device is further provided with an adjustable cam shaft which may disable the first stepping device if less secretive or simpler ciphering is desirable, permitting the drums to be stepped a uniform number of positions each time. For even less secretive or more simple ciphering, the cam shaft may be moved to a position to disable both stepping devices allowing the code drums to remain stationary during ciphering operation. One set of code drums is employed The for controlling the ultimate position of the transmitting levers for transmission while for reception a second set of code drums is provided for determining the ultimate position of the printer vanes.

The invention also provides amodified form of code drums which are individually operable to thirty-two positions to aliord a greater varietyof signal code permutations. Each code drum is individually associated with a ratchet with each ratchet being driven by a pawl .of progressively shorter length. Each ratchet is provided with a special notch, except the one driven by the shortest pawl, the one associated with the longest pawl having the deepest notch, the other notches being progressively less deep. At other positions of the ratchet the configuration of the 'ratchets are identical. The ratchet driven by the shortest pawl has nospecial notch cut therein, its periphery being the same as the, other ratchets, except at the portions whereflthey are notched.

Assuming that the notches of the ratchets are all 'in alignment at the start, the first stepping operation of the, pawls which are mounted on a common arm and'operable in, unison, will advance allthe ratchets one step. On the next stepping operation, only the ratchet with the longest pawl will be advanced. This will continue until this ratchet is stepped completely around at which position the deep notch of the ratchet will present itself for the ,nextste'ppingoperation. On the next steppingpperation boththe longest pawl and the next .to thelongest pawl will step their respective ratchets. On the. immediately following stepping operation only the longest pawl will again step its ratchet. The operation will continue until a point will bereached where all the notches are again. in alignment. Since, mathematically, the codeidrums will not. repeat themselves until theyare stepped. thirty-two to the fifthv powertimes, 33,554,432 key code combinations may be provided before the device repeats itself.

The invention .maybe more readily comprehended by reference to the detailed description which follows when read with reference to the drawings in which:

Fig.1is a front sectional view, taken alongline ll of Fig. 4, in section, of a keyboard controlled transmitter particularlyillustrating the transmitter used in the first embodiment of the invention;

Fig. 2 is a detail view of a portion of the ciphering mechanism;

Fig. 3 is a schematic circuit particularly designed for use with the ciphering mechanism illustrated in Fig. 1; I

Fig. 4 is anendviewof the keyboardcontrolled transmitter taken alongthe line, l4 of Fig. 1;

Figs. 5 and 6 are detail;- views of the ciphering mechanism;

Fig. '7 is achartillustratingthefour possible conditions of the ciphering mechanism during an enciphering operation;

Fig. 8 is an end elevation of atelegraph printer with parts broken away and partly in section to illustrate the main features of the invention;

Fig. 9 is adetail view-of the printer ciphering mechanisms;

Fig. 10 is a detail view of thecoding magnets and armature levers used for the printingoiphering operation taken on the line Ill-4B of Fig. 8;

Figs. 11, 12, andpl-3.illustratedifferent posi-.

Fig. 14 is an illustration of the circuit used to control the. coding magnets;

Fig. 15 is a modified form of the circuit designed for use with the first embodiment of the invention;

Fig. 16 is a view taken ,on line Iii-46' of Fig. 17 of a modified form of the invention illustrating a portion of a keyboard transmitter using key coding drums for ciphering purposes;

Fig. 17 is a plan View of the apparatus shown in Fig. 16;

Fig. 18 is a detail view taken on the line l8-I 8 of Fig. 17 of a pawl and ratchet stepping mechanism used in the modification of the invention shown in Fig. 16;

Fig. 19- is an end view of a portion of the receiver using key coding cams for deciphering;

Fig. 20 is a front elevational detail view taken on the line 2ll20,' of Fig. 19 of the printer ciphering mechanism used for deciphering received signals;

Fig. 21 is a detail view, partly in section, illustrating the key code drums shown in Figs. 19 and 20;

Fig. 22 is a detail view of a cam arrangement for disengaging the stepping mechanism disclosed in Fig. 19; I

Fig. 23 is a detail view of a portion of the stepping mechanism for the key code drums;

Fig. 24 is a view of. a modified form of ciphering for a keyboard transmitter in which the key coding drums are stepped-according to a different arrangement;

Fig. 25 is a partial plan view of Fig. 24;

Fig. 26 is a detaili view of the stepping pawls used in. this modification of the invention; and

Fig. 27 is, a. detail view of the embodiment shown in Figs. 24to 26'as applied to a printer receiver.

Referring particularly to Figs. '1' to 6-, inclusive, the portion ,of the first embodiment of the invention dealing with the keyboard controlled transmitter will be described. At the outset it will be assumed that'for complete details of operation of the type of printing telegraph apparatus about, tobe described, reference should be had to the patent of S. Morton et al., already referred to, and for specific details of operation of the keyboard controlled transmitter per se, reference should be had to the patent of H. L. Krum, No. 1,595,472, dated August 10, 1926.

In Fig. 1 of the drawings a cast metal base is indicated at 2! upon which, is mounted both the keyboard transmitter and, the printing apparatus with which the present, invention is concerned. The keyboard transmitteris controlled from. akeyboard, not shown, wherein depression of'a key lever 22 governsthe positioning of the five-permutation bars 23 housed within the base casting 2|, either to the right or left position. As shown in Fig. 1 the foremost permutation bar 23 is in its leftward or marking positionwith the dotted. line or spacing position of permutation bar 23 being indicated'at 2 3.

Each permutation. bar 23 carries a pair of pins 25 between which ,ispositioneda depending arm 26 of a selecting finger 2'! which is pivoted about the rod 28. Pivotally mounted to each. finger 21 at 29, is a link 3| which carries a pin 32 designed to ride in an arcuateslot 33 formed on a transmittinglever 34.- Each transmittinglever 34 is pivoted on. a rod 35..and is of the conventional I type wherein it closes an associatedcontact pair tions of vthe selectonswords and; ciphering bars for the printing operation;

36 when its lug 31 is permitted to enter a notch 38 of an associated transmitting cam 39. In

addition to'the five transmitting cams 39 the usual sixth start stop cam l8 (Fig. 4) and contact operating lever H) are provided. It may now be seen that when a key lever 22 moves a permutation bar 23 to the right or spacing position selecting finger 21 will pivot at 28 in a counterclockwise direction and when a permutation bar 23 is moved to the left an opposite effect will be produced.

Also mounted within the base casting 2| below permutation bars 23 are five ciphering bars 4| which are under the control of five coding magnets 42, as will now be described. The coding magnets 42 control the position of associated armatures 43 which are pivoted at 44. Upper extensions 45 of armatures 43 engage notches 46 of ciphering bars 4|. Springs 40 attached to armatures 43 are normally eifective to retain cipher bars 4! in their leftward or spacing position. When a particular coding magnet 42 is energized it will attract its armature 43 about its pivot 44 to force its associated ciphering bar 4| to the right, as shown in Fig. 1, to the dotted line marking position indicated at 41.

Mounted on each ciphering bar 4| are a pair of pins 48 which engage a lever 49 pivoted at the free end of which is nested in the bifurcated end 52 of a ciphering lever 53. Each ciphering lever 53 is provided at its upper end with a laterally extending arm 54 having a notch 55 designed to cooperate with the pin 32 carried by arm 3| of selecting finger 21. It is now seen, Figs. 5 and 6, that if ciphering bar 4| is moved to its right, in response to a marking impulse received by its associated code magnet 42, lever 49 will pivot in a clockwise direction thereby pivoting ciphering lever 53 in a counterclockwise position. If, however, its associated code magnet 42 receives a spacing or non-energizing impulse, ciphering lever 53 will be retained in a clockwise position, Fig. 2.

From the foregoing description it is evident by an inspection of Fig. 7 that unlike conditions of pins 32 carried by selecting fingers 21 with respect to the notches 55 of arms 54 of ciphering levers 53 will permit associated transmitting levers 34 to pivot at 35 when its lug 31 is allowed to enter notch 38 of an associated cam '39 as cam sleeve 56 is released for rotation, as

will be explained. This results in a transmission of a marking or current impulse. On the other hand, it is evident that like conditions of selecting fingers 21 and ciphering levers 53 enable arm 54 to block upward movement of pin 32, thereby resulting in transmission of a spacing or no current impulse.

With particular reference to Fig. 3, the circuit for operation of coding magnets 42 will now be described. When it is desired to perform a ciphering operation manual switch 5| is moved to the left in its ciphering position as illustrated in Fig. 3. This operation causes extinguishment of green signal lamp 62 and illumination of red red signal lamp 63 over obvious circuits to indicate that a ciphering operation is taking place.

The code magnets 42 are controlled by means of a key tape 64, which is sensed by sensing levers 55 which control transmitting levers 55 to thereby operate associated contact pairs 61 in the usual manner.

Since there is no coding permutation set up by the magnets 42 at the commencement of a ciphering operation, the first signal transmitted .will be a plain English signal which forms no "part of the message and is transmitted solely to condition the ciphering mechanisms for subsequent operations. When this signal is sent, reference to Fig. 7 Will show that selecting finger 21 and pin 32 thereon will perform its normal function since as shown at A and B in Fig. 7, all ciphering levers will be in their spacing positions as no code magnets are energized. In other words, a plain English signal will be transmitted.

When the first signal is sent by operation of the keyboard, sleeve 56 is released by a single revolution clutch in the conventional manner. When this occurs, locking lever 38 will pivot at 91 under influence of spring 99 in a counterclockwise direction and by means of its blade 98 block movement of selecting fingers 21 and ciphering levers 53 through cooperation with lugs 68 carried by selecting fingers 21 and with lugs 59 carried by arms 54 of ciphering levers 53. At this time apex 51 of cam 53 moves in a counterclockwise direction, as viewed in Fig. 1, and follower 59 carried by locking lever 96 drops to the low part of the cam. Thus, during transmission of the signal by the sequential operation of contact pairs 33, selecting fingers 21 and ciphering levers 53 are held stationary. It should be remembered that in a keyboard transmitter of the type disclosed in the present invention the permutation bars 23 are set immediately upon depression of a key prior to the operation of lockin lever and a single revolution clutch not shown is operated which releases cam sleeve 56 for a single revolution.

Simultaneously with the operation of locking lever 35, contact pair 1| mounted with an insulating portion 12 of blade 13 thereof resting on looking lever 98, are closed and in so closing assist locking lever 96 in its counterclockwise pivotal movement, since normally in the rest position of cam 58 the longer blade 13 of the contact pair 1| is under tension.

Closure of contact pair 1| provides an obvious circuit for clutch magnet 14 which becomes energized and which controls a conventional single revolution clutch, not shown, and there by releases cam sleeve 15 for a single rotation. Five earns 16 fixed to cam sleeve 15 are each cut with a notch 11 at a position timed approximately with the No. 3 impulse of the keyboard transmitter. A sixth cam 18 is also provided which is cut with a notch 19a corresponding approximately to the No. 2 impulse of the keyboard transmitter. The function of the sixth cam 13 is to control the locking circuit for the transfer relays 19 which initially become energized by closure of selected contact pairs 61 depending on the key signals aiforded by key tape 54. This initial circuit extends from battery, through switch 5|, through the winding of relay 19, over conductor 8|, through closed contact pair 61 and over conductor 82 to ground. When front armature 83 is pulled up by relay 19 an obvious locking circuit is provided extending over conductor 84 and through closed contact pair 85. Operation of back armature 86 of a particular relay 19 is effective to provide an obvious circuit over conductor 81 for energizing coding magnets 42.

When cam sleeve 15 is released for rotation upon energization of clutch magnet 14, cam 18 will function approximately during the No. 2 impulse of the keyboard transmitter to open contact pair 85, de-energizing transfer relays 19 by breaking the above described locking circuits and causing therewith de-energization of coding magnets 42 and erasure of key signals stored therein. However, as already pointed out, no coding magnets'uzere energized during the transmission of the first signal but for subsequent signals opening of contact pair 85 will produce the-desired'results. Immediately following the opening and closing-ofcontactpair 85, selected sensing levers 65 which are sensing perforations in tape 64 allow their associated transmitting levers 66' to close contact pairs 61. This enables the energization of coding magnets 42 according to the first key signal. Ciphering bars 4| maymove to their selected positions as locking lever 96 is raised by the follower 59 when the rest position of sleeve 56 is approached.

When the operator depresses a key to send the first enciphered signal, a key signal will-have been stored in coding magnets 42 and ciphering bars 4I'will have been set accordingly. The depression-of the key will immediately shift permutation bars 23 in accordance withtheoriginal signal. The locking lever 96 will now lock the selecting fingers 21 and the ciphering levers 53 during transmission of an enciphered signal to an outgoing line. The operation of transmitting levers 34 will of course be determined by the'joint control exercised by selecting fingers 2'! and ciphering levers 53', as graphically represented in Fig. 7, thus ensuring the transmission of an enciphered code signal.

With particular reference to Figs. 8 to 14, inclusive, the printer ciphering mechanism used for deciphering incoming signals transmitted by a keyboard transmitter, such as disclosed in Fig. 1, will now be described. Numeral IDI indicates generally the printing portion of a combined printing telegraph apparatus similar to the apparatus disclosed in the patent of s. Morton et al. referred to above. In this type of printing apparatus, incoming signals are received by a selector magnet I02 which operates an armature I03 in accordance with received signals which in the instant case are enciphered signals being received from a distant station. Connected with armature I83 is an armature extension I84 whose arms I and I86 are designed to cooperate respectively with arms Ill! and IE8 of five swords I09. In each operation of the swords they are moved back and. arms II'J'I or I68 respectively engage either arm I65 or I86 of armature extension I64 according to incoming signals, resulting in the shifting of the swords to either their marking or spacing position so that on the forward movement thereof the pointed end of the sword will engage either surface III or N2 of levers H3. The reciprocation of the swords I 09 is accomplished by means of a cam sleeve, not

shown, which is controlled by a conventional single revolution clutch. This type of selector is well known in the art and its operation is completely disclosed in the Morton et al. patent.

Ordinarily swords IDS control the operation of the printer selector vanes H4 by means of a series of T-levers not shown in the present invention since the type of printing telegraph apparatus herein disclosed is designed for performing deciphering operations in addition to operating to receive plain English signals. Levers IE3 which are .pivoted at III] and have a limited movement afforded by the pin H5 and slots H6,

have a projecting end .I I! designed to cooperate with a projecting-endl I8 of ciphering slides II 8. Therelative positions of the projectingends Ill and H8 willdetermine whethera vertical slide I 21! which has a rounded arm 122 in engagement with-slot-l23 of cipheringslides H9 will be permitted-to move up, when the' vanes IN-are not locked, by'bell cranks I24 pivoted-at' I25 and'nor--v mally' urged in a counterclockwise direction-by springs I26. The positions of slides H9 are governed by operation of armatures I'26a'ofkey coding magnets I27 to which they are pivotally attached at I28. Armatures I26a are normally urged in a clockwise direction as viewed in Fig. 8 about-shaft I29'by springs I58. Articulated to each vertical slide I2I by bifurcation I20-are the vanes H4 which are normally in their spacing position but pivot to a clockwise or marking position when an associated slide I2I is permitted to move upward. It should be mentioned at this time for the sake of clarity that the normal position of the slides H9 to the left is the spacing position while the position to the right is the marking condition. Likewise, the position of levers H3 to the right is the marking position while the position to the left is the spacing position. When a nonblocking or marking condition exists with respect to projections II! and I I 8, slides I2I will be enabled to move up, thereby actuating associated vanes II4 to their marking positions. If likeor blocking conditions exist be tween projections I I! and I I8 it is apparent that slides I2I will not be able to move up and the associated vanes III; will remain in their spacing position. These blocking and nonblocking conditions are illustrated in Figs. 8 and 11 to '13.

For controlling the ciphering operation the printing cam I3! mounted on sleeve I32 (Fig. 9) is utilized. Printing cam I3I is a standard part of printing telegraph apparatus of this type and controls the operation of the printing bail, not shown, which operates a selected pull bar also not shown, the selection of which is controlled by the printing vanes II4. In the pathof the high part of printing cam I3I is normally positioned a-follower I33 carried by lever I34 which is pivoted near its rear extremity at I35. The front end of lever I34 is slotted at I36 whereat it is engaged by a pin I3! supportedon a T-shaped lever I38 which includes a bail I4I which overlies arms I22 of the vertical slides I2I. T-shaped lever I38 is normally urged in a clockwise direction as viewed in Fig. 8 by means of spring I63. The T-shaped lever I 38 is pivotally connected at I4Ia to a rearwardly extending lever I42, therearward extremity of which normally holds a contact pair I43 in its open position.

The circuit shown in Fig. 14 for controlling the operation of coding magnets I2! will now be described. For deciphering incoming signals, akey tape I44 is provided which is identical with the 'key tape at'the transmitting station and occupies the same relative position. To sense perforations in tape I44 a series of tape sensing levers I45 are provided which control the operation of transmitting levers I 46 in the usual manner to permit contact pairs M! to close or remain open depending upon the permutation afforded inkey tape I44.

When a particular sensing lever I45 moves into a perforation allowing closure of a contact pair I4! a circuit is made for an associated transfer relay I48. Attraction of front armature I49 provides an obvious locking circuit for transfer magnet I48 extending over common conductor I5I and through contact pair I52 which is under the control of a sixth cam I53 notched approximately for operation during receipt of the N0. 2 element or impulse by the receiving selector magnet 182. The five transmitting cams I54 which control contact pairs I47 are notched approximately for operation during-receipt of the No. 4

element or impulse by selector magnet I21. When armature I55 of transfer relay I48 is attracted an obvious circuit is provided for its associated coding magnet I21.

In order that the invention may be properly understood a typical deciphering operation will now be described. At the commencement of the deciphering operation by prearrangernent with the transmitting station, manual switch I56 will be moved to the left which extinguishes the green signal lamp I! and illuminates the red signal lamp I58 indicating a deciphering operation is taking place.

It will be recalled that to start the keyboard transmitter disclosed in Fig. 1 into operation a plain English signal forming no part of the message is transmitted over the line. This plain English signal has the additional function of conditioning the printer for subsequent deciphering operations. When this first signal is received by selector magnet I02, swords I09 will be positioned according to the signal code combination received. Towards the end of the revolution of the cam sleeve, not shown, controlling the swords I09, cam sleeve I32 will be released by operation of its clutch throwout lever I which is under the control of the sword cam sleeve. Upon the first release of cam sleeve I32, printing bail cam I3I rotates and its high part engages follower I33 of lever I34 which now pivots about its pivot I in a clockwise direction, and through the engagement of its slot I36 with pin I31 carried by T-lever I38, pivots T-lever I38 in a counterclockwise direction, lifting the bail I 4| from holding engagement with arms I33 of vertical slides I2I. Selected vertical slides I2I will now move up through operation of bell cranks I24 by their springs I23 and operate vanes II4 accordingly. In this connection it should be remembered that at the commencement of a ciphering operation all ciphering slides I I9 are in their leftward o1 spacing position, in which position levers H3 will be set to permit plain English signal code combinations to be transferred to the vanes II4.

Shortly after the vanes I I4 are set for the signal code combination, the function bail, not shown, locks the vanes during the printing operation. The function bail is controlled by a function bail cam I59 (Fig. 9) which is mounted upon the cam sleeve I 32. In the latter part of the revolution of cam sleeve I32, after the printing operation is performed, vanes II4 are again unlocked, but at this time bail II of T-lever I38 is prepared to assume a position resting on arms I22 of vertical slides I2I holding the vertical slides I2I in their downward position. This is due to the fact that in the latter part of the revolution of printing bail cam I3I, a low part thereof is presented to the follower I33 of arm I34 and spring I33 therefore functions to pivot T-lever I38 in a clockwise direction.

It should be remembered that while cam sleeve I32 is rotating, a new signal or the first enciphered signal is being received by selector magnet I02 and the swords I09 are being set to a new position. At this time levers II3 may not be able to move to their new position due to the fact that the vanes may be locked and bail I4I of T-lever I38 is in its upward position, permitting some projections I I1 and I I8 to block each other. However, since swords E03 reciprocate and pivot in each cycle of the operation, in their backward stroke they will acquire their new setting and in their forward movement rest against either surface III or surface II2 of levers II3. When,

vanes II4 are unlocked and bail I4I moves to its downward position upon the second release of cam sleeve I32 the swords I09 may now position levers I I3 in accordance with the first enciphered signal. Therefore, by reason of the locking of the vanes II 4 and operation of bail I4I a new character may be selected while the previous character is being printed, thus providing a sig nal overlap arrangement as is usual in this type of printing telegraph apparatus.

As cam sleeve I 32 started to rotate, towards the end of the reception of the first or plain English signal by selector magnet I02, T-lever I38 was pivoted in a counterclockwise direction thereby moving the rearwardly extending lever I42 to the right permitting closure of contact pair I 43. This provides an obvious circuit for a clutch magnet I 0! (Fig. 14) which causes operation of a single revolution clutch, not shown, releasing cam sleeve I32 for operation. It should be borne in mind that at this time the second signal or first enciphered signal code is being set up by swords I09 as explained. Approximately during reception of the No. 2 impulse by selector magnet I02 cam I53 will open contact pair I52 breaking the locking circuit extending over conductor I5I for transfer relays I48. However, since none of the relays I43 are energized during reception of the first or plain English signal no circuit is actually broken but on subsequent operations previous signal code combinations stored in transfer relays I48 will be erased and cause a corresponding erasure of the signals stored in coding magnets I21. Approximately during reception of the No. 4 impulse by selector magnet I 02 sensing levers I45 will feel for perforations in the key tape I44 set to the same position on the identical key tape at the transmitting station and accordingly contact pairs I41 will be permitted by cams I54 to close in the permutation afforded by the key tape I44 at this time. Selected transfer relays I48 will thus be energized and immediately lock up sin e contact pair I52 is again closed at this time. As selected code magnets I2I are energized at this time they attract armature levers I2Ba in a counterclockwise direction about the rod I29, thereby tending to'move associated ciphering slides I I9 to the right or marking position. Since the vanes II4 are unlocked approximately during the receipt of the No. 4 impulse by selector magnet I02 while the tape sensing operation is being performed, selected slides II9 may be temporarily restrained from operation depending on the exact timing if their projections II8 interfere with the projections II! of levers II3. However, as soon as the vanes II4 are unlocked slides II 9 may move to the right since coding magnet I21 at this time remains energized.

Towards the end of the second revolution of the cam sleeve which controls swords I09, cam sleeve I32 is released for operation, cam I3I operates against follower I33 of lever I34 to thereby pivot T-lever I38 in a counterclockwise direction removing bail I4I from the path of arms I22, of selected vertical. slides IZIpermitting them to assume their upward position. Shortly thereafter, the vanes II4 are locked and retained in their locking position during the printing operation in which a deciphered plain English signal will be'printed. The deciphering operations will continue in the same manner for the remaining portion of the message.

In the just described embodiment of the invention for accomplishing key coding operation two key coding devices are employed in the form of "ceiver I10. paratus is disclosed in the S. Mortonet a1. patent previously referred to above. 'thatin addition to the standard printing telegraph equipment each station will be equipped with identical key coding devices.

code signals.

:key tapes, one being used=forenciphering or transmitting purposes and the other being employed for deciphering or receiving purposes; In a modification of this embodiment of the invention there is provided a control circuit whereby a single key' cipheringdevice in the form of a key tape sensing mechanism may be used for both enciphering and deciphering operations. With ref-'- -erence particularly to Fig. 15 of the drawings this modification will now be described.

Numeral IB-represents a local station which includes a combined keyboard transmitter I66 and printing receiver IOI while a distant station is represented as numeral I88 and includes a combined keyboard transmitter I69 and printing re- This type of printing telegraph ap- It is understood By-this modification of the invention atransrnitting station will send enciphered signals to an outgoing line which willbe repeated in the receiving circuit of the transmitting station and deciphered to thereby print a plain English home record.

A key ciphering tape is represented by numeral 'I'II and controls the selective operation of sensing levers I12 which govern the operation of transmitting levers I13 and is thereby effective to permutatively regulate the closure of associated contact pairs I14 in accordance with key For enabling the permissive operation of transmittin'g'levers I13, there are provided the usual transmitting cams I15 which in this instance are all notched at I16 for approxisleeve I32 (Figs. 8 and'9) is operated. The closure of selected contact pairs I14 enablesthe selective operation of primary storage relays I80 according to key signals under certain circuit conditions to be later described. The primary storage relays I80 selectively govern the operation of double wound relays I19 and IBI, which respectively control the energization of-selected transmitter coding magnets I82 and selected receiver I coding magnets I83.

In addition to the five transmitting cams I15 there are provided on cam sleeve I11, cams I84, I85, and I88 which respectively control make before break contacts I81, I08, and contact pair I89 by means of levers I9I, I92, and I93, respectively. Cam I84 is notched at I94 to correspond approximately with the start impulse position of the cam sleeve I11; cam I85 is similarly notched at I95v for the No. 2 impulse position, and cam I86 is similarly notched at I 96 for the No. 3 impulse position. These so called impulse positions representpositions in the rotation of the camsleeve I11 which correspond to the'usual I five positions and start-stop positions of the Baudot code.

Whensensing levers I12 sense'perforations in the keytape I1I, selected contact pairs I14 will be closed energizingselected primary relays I80 over conductors I94 under certain operating conditions which will later appear. When a primary relay I80 is energizeda locking circuit therefor is provided through attracted armature 495, over conductor 496 and through'contact pair I89 controlled by cam I86. Attraction of armature I 91 by a primary relay I prepares acircuit for transferring a selection from a primary relay I80 to double wound relay I19; when the normally open pair of the make before break contacts I81 are closed, over conductors I98,through armature I91, over conductor I99 and through the left winding of double wound relay I:19.

Energization of a double wound relay I19 causes the transfer of the selection to an associated transmitter coding magnet I82 by attraction of armature 205 while attraction 'of its armature 205 provides a locking circuit for double wound relay I19 extending through its right winding, through armature 206, over conductor 201 and through the normally closed contact pair of the make before break contacts I81.

Attraction of armature 208 by a primary relay I88 prepares a circuit for transferring a, selection from a primary relay I80'to a double'wound relay I8I, when the normally open pair of the make before break contacts I88 areclosed, over a conductor 209', through armature 20B, overa conductor 2H and through the right winding of double wound relay I8I. Attraction of' armature '2I2 by a double wound relay II8I transfers a selection to associated printer receiving coding magnets I83 while attraction. of its armature 2I3 provides a locking circuit for double wound relay I8I extending through its left winding, through armature 213, over conductor 2'I4 'and through the normally closed contact pair of the make before break contacts I88.

To facilitate a ready understanding of this modification of the main embodiment of the invention, a description of a typical ciphering operation will now be undertaken. At the commencement of ciphering operations manual switch Hill is moved to the left extinguishing green signal lamp 2I5 and illuminating red signal lamp 2I6, overobvious circuits and indicating thata ciphering operation is takingplace; In order to condition'both the local station I85 and distant station I68 for ciphering operations two plain English signals chosenxat random are first transmitted which form no part of the message proper. It is necessary that these two plain English signals be transmittedin order that the control circuit be conditioned to aiTord key ciphering signal code combinations for both the transmitter and receiver at a given station. All signals sent over the line 2I3 to distant station I88 will be repeated by the selector magnet I02 at the local station and printed after being deciphered by the receiver IIlI.

Upon the transmission of the first plain English signal, cam sleeve I32 (Fig. 9) is released as explained by operation of clutch throwout lever I38 which immediately results in the closure of contact pair I60, providing an energizing circuit for clutch magnet I18 extending over conductor I88, thereby releasing cam-sleeve I11. 'When cam sleeve I1? is released, make before break contact I81 operates to erase the previous selection existing in code magnets I82 during the start interval of cam sleeve- I11 by opening the locking circuit for double wound relays I19, thereby causing deenergization of the associated code magnets I82.

However, during the first revolution of cam sleeve I 11 no coding magnets I82 are yet energized. When make before break contact I81 operates to erase the selection previously existing in code magnets I82, it also functionsto acquire a new selection for the code magnets I82 from, primary storage relays. I88 but again-it must be remembered that at this time no primary relays I 80 are yet energized. Make before break contacts I88 function in the same manner as contacts I81 but during the No. 2 impulse period of cam sleeve I11. During the No. 3 impulse period, contact pair I 89 opens to erase the selection existing (if one had existed) on primary relays l80 by breaking its locking circuit. When cam sleeve I11 reaches its No. 5 position as the sensing levers I12 operate, the first ciphering selection will now be acquired for primary storage relays IBII.

When the second plain English character is transmitted, contact pair I60 will be closed by clutch throwout lever I as described releasing cam sleeve I11 for its second revolution. During the start impulse, make before break contacts I81 operate as before but now enable the double wound relays I 19 to acquire the selection existing in primary storage relays I80 and transfer the first key ciphering selection to transmitter coding magnets I82 which look up as previously described. Make before break contacts I88 will perform a similar function for receiver code magnets I83 during the No. 2 period of operation of cam sleeve I11. During the No. 3 period, contact pair I89 will open to erase the selection existing in the primary relays I80 which will acquire the second ciphering selection from key tape I'II when cams I15 reach the No. 5 position as tape sensing levers I12 operate.

Now when the keyboard transmitter I65 is operated a third time, ciphering bars 4| (Fig. 1) will have been set to the positions representative of the first key ciphering signal and accordingly the first enciphered signal will be transmitted. Likewise ciphering slides H9 (Fig. 8) will have been set to positions representative of the first key signal and receiver I ill will function to decipher the first enciphered signal repeated by selector magnet I02 to print the character in plain English form. As cam sleeve I11 is released for the third time it should be mentioned that the make before break contact I88 is timed to operate after the printing vanes lock to insure that the same key signal used for enciphering will be used for deciphering. The cycles of operation described will now be repeated as the remaining portion of the ciphering operation pro- 'ceeds. It is obvious from an inspection of the circuit shown in Fig. 15 that the ciphering system may be operated in either direction of transmission, with the identical key tape at each station occupying the same positions.

Another modification of the invention disclosed in Figs. 16 to 23 inclusive wherein a series of key Coding drums 225 which afford a large number of key code combinations are substituted for the key ciphering tape, will now be described. The drums 225 are notched promiscuously to represent marking and spacing conditions to provide key ciphering code combinations. It is assumed of course that a, transmitting and a receiving station will be equipped with identical key coding drums 225 which will be set to like positions, there being a total of thirty-two positions for each code drum. The first portion of this modiflcation to be described relates to the ciphering mechanism to be used with a keyboard transmitter indicated generally as 226 which is simi lar to the keyboard transmitter illustrated in Figs. 1 to 7 inclusive.

Journalled on the frame member- 221 and 228 (Fig. 17) is a shaft 229 to which is fixedly attached-a'ratchet 23I which'is-stepped one position by a pawl 232 in each cycle of operation as will later be described. Freely rotatable about the shaft 229 is also mounted a cam sleeve 233 to which is fixedly secured a ratchet 234 which is variably stepped either one or two positions or not at all in each cycle of the operation by a pawl 235, as will also later be described.

A series of sensing levers 236 are pivoted on rod 231 and urged in a clockwise direction as viewed in Fig. 16, into engagement with the pe-' riphery of associated code drums 225 by means of springs 238 which enables pointed arms 239 of sensing levers 236 to feel the periphery of the code drums 225 according to marking or spacing conditions. Depending arms 24I of the sensing levers 236 are in engagement with associated ciphering levers 242 which are pivoted at 243 and normally urged in a clockwise direction by means of springs 244. Thus, depending on whether a high part or spacing condition of coded drum 225 or a notch or marking condition presents itself to arms 239 of the sensing levers at a given time, individual ciphering levers 242 will either be retained in their leftward or marking position or will be allowed to move to their rightward or spacing position.

Selecting fingers 245 are under the control of the permutation bars 246 which are set to marking or spacing positions when the keyboard is operated as described in the main embodiment of the invention. Selecting fingers 245 carry links 241 which are pivoted at 248 and have secured thereto pins 249 which are designed to ride in arcuate slots 25I of the transmitting levers 252.

The relative positions of pins 249 with respect to the notches 253 of ciphering levers 242 govern the operation of the transmitting lever 252 to allow transmitting contact pairs 254 to remain open or closed according to enciphered signals. The permissive operation of transmitting contact pairs 254 is accomplished in the usual manner by a series of five transmitting cams 255, Fig. 17. A sixth cam 256 is provided for sending start-stop impulses in the conventional manner by controlling contact pair 251. The operation of ciphering levers 242 and selecting fingers 245 may be readily understood by reference to the chart illustrated in Fig. 7 of the drawings and previously described.

The pawl 232 is pivotally connected to look. ing lever 251 at 258 which is urged in a counterclockwise direction about the pivot 259 by means of spring 26I to place its follower 262 normally in contact with the high part 263 of cam 264 which is mounted on cam sleeve 265. Therefore, from the above description, it is obvious that in each operation of cam sleeve 265, shaft 229 will be stepped one position in a clockwise direction as locking lever 251 moves down and returns to its upward position. Fixed about the shaft 229 for movement therewith is a variable feed disc 266 whose periphery 261 (Fig; 18) is notched at two difierent levels 268 and 269 for a purpose which will later appear, there being thirty-two positions of the disc 266, equal to the number of teeth in ratchet 23I.

Pivotally mounted at 21! (Fig. 18) is a feed control lever 212 which is normally urged in a counterclockwise direction into engagement with the periphery of cam 213 carried by cam sleeve 265 by means of a spring 214, at its follower surface 215. Fixed for pivotal movement with lever 212 is an upstandin sensing arm 218 having' a pointed 811111219. which feels the periphery 261 of variable feed disct266. Pivotally attached to. the;- feed; controlrlever; 2212" at; 2N is the step ping pawlr235vwhichis urged-into engagement with. the. teeth of ratchet .234 by meanslof a spring 2181:;

It now can beseen thatzaccording-tothe positionof, the pointed end-.;2l9-.of sensing. arm 2'33 upon the periphery. 2310f variable feed disc 233 the control lever 232 may be permitted to. pivot in a counterclockwise. direction. by theaction of spring 214 either to one position determined'by level 268, or another position determined by level 269 or no movementat allwillbe permittedwhen the pointed'encl 213; engages: the. outer periphery 26.1 of the variable feed-disc 255. This pivoted movement is permitted uponrotation of; cam sleeve 235 when a low partisreached on. cam 273 by follower 2'i5 of-control lever 212: Aathe follower 215 rides to the high part of cam 273-, ratchet 234 is accordingly-stepped one, ortwo positions by thepawl 235 or-is allowed to remain in its same position. The code drums 225 carried by cam-sleeve 233 will .thus be setto their various positions. Thezpawl- 232 operates ratchet 23! forward one position foreach operating cycle towards the end of rotationof cam sleeve I235 as follower 262 of locking lever 25? rides-upon the high part 263 of cam 264 as has been already described. To insure retention of the code drums 225 in their various positions a detent' 28!. is provided which is pivoted at. 2'5! and normally urged in a counterclockwise direction by means of spring 282 into engagement with theteeth of ratchet 234'.

In order to set each of the code drums 225 at a particular position upon the commencement of a ciphering operation, twoindicator dials 233 and 284, having thirty-two positions and a fixed pointer 285 are provided. The dial 2831s fixed for rotation with shaft 229' and dial 284' is rotatable with the cam sleeve 233. Thus by a prearrangement the dials 283- and 284 may beset to any one of their thirty-two positions at the transmitting and receiving station so that identical key code signals are afiorded foryboth en-. ciphering and decipheringoperations.

For. simple ciphering operations there may be provided inconnection with this modification of the invention a manually rotatable. shaft 24! (Fig; 22) suitablypositioned below pawls 232 and 23.5.. i which operates pawl 23-2:and-a second cam member 233. which operates" pawl 235. By. this arrangement a set screw not shown could be in-. serted in camsleevez233 at a threaded opening 294- to lock the sleeve to shaft 22-3.; Cam 293 may then be turnedrby; knob 235st!) -a.-position to disengage pa-Wl 235 from the-ratchet 234; Thus cam sleeve 233;- Would. be stepped one position for each operation. of the paw1'232. For even simpler ciphering; kn0b;235;may; be-turned to a position to disengage-both pay/1. 5232 and 235' from their associatedratchets sea-that the code drums 225' remain in 'afixed. position.

The modification-ofthe invention'whichzutie lizes code drums in place of a key ciphering tape will now be described in connection/with the printer: receiving unit, with particular reference to Figs. 19 to Zlinclusive.

Numeral 34.5rrepresents the selector magnet which receives, incoming. signals: and accordingly positions the sworcls306rto either their mark-. ing or spacingpositions, as 'is more completely described in an. earlier. part of: thespecification, to engage either surface 01:30.8..of 111163161 81 Shaft, 29L carries cam. member 292 30.9, to pivot-thelevers aboutpivot-BlL-so that the-projecting edges 3l2-thereo f, move.- either'to their right ormarking. positions, or to:.-their left or spacing positions. Projections. 3i2 are designed to cooperatewiththe projections 353 of the ciphering slides 3l4-tol determine: whether vertical slides 395 will be permittedto move to their upward position, or. will remain in their downward position; to operate vanes 3E3.- by means of the bifurcations. 35-? to marking or spacing positions. Upwardmovement of; slides 3H3 is accomplished by means of bell cranks 318 which are pivoted at 3|9 and-normallyebiasedin a counterclockwise direction 'bynieans'of spring 3211'.

Slides 3l5 will be enabledto move upwardly when projections 3L2 and 393 are ofiset with respect toeach other, indicating opposite signal conditions, that is, one being in the marking position and the other in the spacing position. Release of the slides M5 is permitted when the printing vanes 3i3-are unlocked and ball. 3H) carried by T-lever. 322 is. moved upwardu T- lever 322' is pivoted at 323'1andrnormallyurged in aclock-wise directionbymeans of'spring 324. Carried by the T lever 322 is a pin 325- designed to ride in the bifurcation 323; of the. operating lever 32? which is-pivotedat 323 and includes a follower 329' for engaging the periphery of printing bail cam 33 The positioning of theiciphering; slides 31.4 is controlled by means of keycode drums 332-which are notched promiscuously to'indicate marking or spacing conditions. Code drums 332-; are mounted upon and rotatable with cam sleeve 333 about shaftj'334' journalled on the frame members 335 and 335.- Attached-.110 slides 3M near the rearward extremity thereof are pins 33'! designed to ride inthe slots 338 of sensing levers 339 which are-pivoted about the. rod 341 and urged in a clockwise direction by springs 33!]. Sensing levers 339* are connected to the ciphering slides 314 by-means of springs 342 so that as projecti0ns'343' ofjthe sensing levers 333 feel the, periphery of the code drums. 332; ciphering slides 314 tend to followthe movement of sensing levers 339".

For accomplishing the: stepping: of the code drums 332; a' stepping arrangement such asdescribed in connection with the transmitting porion of the invention isemployed. Fixed tOtShEtft 334 (Fig. 21) journalled on frame members 335 and 335 is a ratchet 344 which is driven by pawl 345 pivotally connected at 343 to lever 34-! which is pivotally mounted. on.rod 348; A spring 349 (Fig. 23) urges the pawl. 345- into. engagement with the teeth of ratchet 344. Lever 341. is pivotally connected. at 35!:- to one end of lever 352, which at its other endis pivotally. connected at 353 to thedepending; arm354 of T-lever 322. Thus, upon each rotation. of cam 336. operating lever 32'! will pivot T-lever 322.111. acounterclockwise direction removing bail 3H] fromem gagement with the base of slides 3l5'andcause ing lever 35.2 to be reciprocated therebyv operating lever 34'! and pawl 3.45, to steplatchet 344 and shaft 334 forward one position.

Fixed-for rotationwith shaft. 334 is a variable feed control disc 355:similar. tothe. disc 266, previously described in connection with the transmitter, having an: outerperiphery 353, a first level notched at 351 and a secondv level-notched at 358, which.is'sensedl-byv a sensing; arm. 35.3 integrally formed asv part of-leyer. 33 l, which-pivots about 5 rod 343; and is.--normally urgeddn .a. 0106K? -wise direction :by means of a spring 362. Bivotally connectedat 350 :to lever 36! is a stepping pawl 364 which is .urged into engagement with gagement with a suitablyrmounted fixed pin369. Slidable lever 363 is normally retained in its leftward position by means :of the printer function bail 31! which is operable bya function bail cam, not shown, and in each cycle-of operation moves .to the right and returns to its leftward position. Thus, according to .the operationof sensing arm 359 slidable lever 363 may be allowed to .move to the right due to the action of spring 362 to follow function bail 31! and will bepushed to its leftward position as .the function-bail 31.! returns to its normal position. This reciprocable movement of slidable lever 1363 if allowed by sensing .arm 359 of lever .36! enables pawl-.334 to step ratchet 365 either one or .two positions. If lever 36! is not permitted tomove .atall by sensing .arm 359 engaging the outer periphery 356 of disc 355, ratchet 365 will remain in its same position. It .is understood that suitable detents, not shown, Will be provided for ratchets 344 and 365 .to retain them in their diiferent positions.

A typical deciphering operation will .now be .described in order to facilitate a ready understanding of this portion of the invention. As the first enciphered signal is received by the selector magnet .395, swords 306 are positioned according to the signals for operation of levers I Ciphering slides 3!4 will bein the last position according to the code presenting itself to projections .343 of sensing levers 339. .As printing bail cam 33! is released for operation near the end of the receiptof .the .firstsignal, as explained in an'earlier part of the description, fol- .lower 329 of lever 32-1. is engaged causing T-lever 322 to be pivoted in a counterclockwise direction removing bail 13!!! from engagement with -the base of vertical slides 3 5, allowing selected slides 3!5 to move upwardly to operate vanes .3!6. Shortly thereafter, the printing vanes lock and a plain English deciphered signalis printed.

As the T-lever 322 is pivoted as explained above, lever 352 is moved to theright and'later returns to the left stepping ratchet 344 forward oneposition as will be described hereinafter. Before lever 352 returns to the left, however, .arm 359 of lever 36! feels for a new level, as function bail 31! moves to the right, upon the variable feed disc 355. If permitted to do so by the variable feed disc 35-5, lever 36! will pivot .in a clockwise direction one or two steps and upon the return movement of function bail 31!, will step ratchet 355 and code drums 312 one or two'positions. Of course, if no .pivotalmovement of lever 36! is permitted, no feeding'of-ratchet 355 will take place.

As'cam 33! rotates, the printer'vanes 316 are unlocked but prior to this time, ball 3!!! is ready "to move to a position holding vertical slides 3!5 in their downward position since a low part of cam 33! will nowbe presented to follower 329 of lever 321 and spring 324 will pivot T-lever322 'in a clockwise direction. Clockwise pivotal-move ment of T-lever 322 moves lever 352 to theleft to therebyenable pawl 335 to step ratchet-i344 to its next position. At this time ciphering slides 3M -may move to their next ciphering position if they have been previously blocked by :inter- *ference .of their projections 3! 3 KWith projections 23:8 3. !-2-'of, '1evers 3119. Likewise, :levers 369 may .as-

sume the new setting determined -.by receipt of the next signal by selector magnet .395 and the position of:swords 306. This belated movement of slides 3l4 may be permitted-due to thespring connection existing between slides 3.! 4 and sensing lever -339, provided by springs 34.2.

For setting the .code drums 332 to their starting positions bya prearrangement with another station, indicator dials 41!, 312 and-apointer-313 are provided. Dial 41! is rotatable with.sleeve 333 while dial 312 is rotatable with theshaft. 334.

.A .modified form vof stepping arrangement .for a set of coding drums 315 for use in connection with a keyboard transmitter is disclosed in Figs. 24 to 26 which afford ,a .great number of key cipher signals. Actually .the five coding drums 315 which are independently rotatable -.to thirty- .two different positions afford 33,554,432possible combinations before .repetition, which is mathematically, thirty-two to .the fifthpower.

Each code.drum.315 isfixed to a ratchet 316, whichtogether aremounted .onindividualsleeves 31.1 for rotation about theshaft318 journalledin framemembers 319 rand-38!. :For retaining .the ratchets 316 in position, detents 382 are .pro- 'vided which are urged into engagement .with :the teeth of rratchets 316 by means .ofsprings 38 3. Four of the individual ratchets- 316 .are stepped by pawls 384 of progressively shorter lengths which are mounted for pivotal movement .and

move as a unit about a common shaft .385 :car-

"notch 381, the one associated "with the longest pawl 384 being the ratchet viewed-at the top pf Fig. 25 which has the deepest notch-.381. Otherwise, the contour of the ratchets-315" at..its-other thirty-one positions is similar -.to the lowermost ratchet-315 shown in Fig. 25 which is designed to be engaged by the shortest-pawl384-and whose teeth are thesame at all thirty-two rpositions.

Assuming that the notches 3.81 of the z-fourzuppermost ratchets .316 are in alignment, the :next stepping operation of the pawls, provided by tthe operation of locking lever 38!], will advance all the ratchets 31-6 andtheir associated code-drums 3 5 one position. 'On thenext-steppingioperation only the ratchet 316 engaged-'by-the longest pawl 384 will be advanced since the other four pawls 384 will be held out of engagement with the teeth-of their respective'ratchets 316. The

stepping operation of the longest pawl 1384 will continue until the deep notch381 provided in its associated ratchet .316 is again "encountered by its associated pawl 384. At this'time'rthe longest pawl 384 '.will fall partially into ithe notch 381 and allow the next longestpaw1384-t0=engage a normal tooth of its associate'd'ratchet to advance it one step. On the "immediately following stepping operation only the longest pawl 384 will again step its ratchet 316. The'opera'tion will continue in this manner until a point willbe reached where all the deep'notches 381aare again in alignment.

Depending arms 3880f sensinglevers 389- which are pivoted at 31! control the positioning .of ciphering levers 392 as is more completely adescribed in connection with sensing levers .1236 disclosed in Fig/16. Springs-393urgesensingdevers 389 .in a clockwise direction into engagement with the key: coding. drums 1315, :toztherebyrsense Cam sleeve 39I 19 the periphery of the code drums 315 for marking or spacing conditions.

-The application of this modification of the invention for use in the printer receiver will now be described with particular reference to Fig. 27. represents the sleeve of the printer receiver on which is mounted the usual printing bail cam and function bail cam previously described. Fixed to cam sleeve 39I is an added cam 392 which by means of its high part 493 operates a follower 394 pivoted at 395 and urged in a clockwise direction by a spring 396. Pivotally mounted to, follower 394 at 391 is a lever 398 which at its other end is pivotally mounted at 399 to one of a pair of spaced levers 40I, only one of which is shown, and which are pivoted about the rod 402. pivot rod 403 designed to carry a series of step- Supported by levers. 40| is a ing slides 409 are the equivalent of sensing levers 339 and ciphering slides 3l4 disclosed in detail in Figs. 19 and 20.

In operation, after the vanes of the printer have been locked upon rotation of cam sleeve 39 I,

high part 493 of cam 392 is efiective to operate follower 394 to thereby cause actuation of the stepping pawls 404 as levers 40! pivot about the rod 402. Details of operation of the stepping pawls 404 and ratchets 406 have already been described in connection with similar members shown in Figs. 24 to 26 and a repetition of that description is deemed unnecessary.

Various changes and modifications may be made in the above described invention without a departure from the spirit and scope of the invention as defined in the following claims.

What is claimed is:

1. A ciphering device including a set of key coding instrumentalities having promiscuous representations of opposite telegraph signalling conditions, means for advancing one of said instrumentalities and retaining other of said set stationary under certain operating conditions, means foradvancing one or more of said instrumentalities under other operating conditions, a set of ciphering levers positionable in a key code combination according to the representative code combination presented at a particular time by said instrumentalities, a set of selecting members, and a set of transmitting members controlled jointly by said ciphering levers and said selecting members.

2. A ciphering device including a set of key coding drums having promiscuous representations of opposite telegraph signalling conditions, means for advancing one of said code drums independently of the others, means for enabling the unitary advancement of one or more of said code drums, a set of ciphering levers positionable in a key code combination according to the representative code combination presented at a particular time by said coding drums, a set of signal controlled selecting members, and a set of transmitting members controlled jointly by said ciphering levers and said signal controlled selecting members for transmitting enciphered signals.

3. In a ciphering transmitter, a plurality of slidable permutation bars operable according to code combinations, an equal number of selecting fingers controlled by said permutation bars, a like number of key code combination responsive ciphering levers, a ciphering device for controlling said ciphering levers and including a set of key coding drums having promiscuous representations of opposite telegraph signalling conditions, means for advancing one of said code drums independently of the others, means for enabling the unitary advancement of one or more of said code drums, said ciphering levers being positionable in a key code combination according to the representative code combination afforded at a particular time by said coding drums and a set of transmitting levers operable under the joint control exercised thereover by said selecting fingers and said ciphering levers for transmitting enciphered telegraph signals representing a combination of said code combinations operating said slidable permutation bars and said key cod-e combinations positioning said ciphering levers.

4. In a ciphering selector, a plurality of code combination controlled members, a like number of key code combination controlled members, an equal number of selectable elements jointly controlled by said first and second mentioned members, a plurality of key code drums positionable to a variety of positions for controlling said second mentioned members, a plurality of advancing means for advancing said plurality of key code drums to said variety of positions, each individual one of said plurality of advancing means being associated with and being designed to advance a corresponding one of said plurality of key code drums, means for operating said plurality of advancing means, means for insuring the advancement of one of said key code drums by its corresponding advancing means under certain operating conditions, and means for enabling the advancement of more than one of said key code drums by their corresponding advancing means under other operating conditions.

5. In a ciphering selector, a plurality of code combination controlled members, a like number of key code combination controlled members, an equal number of selectable elements jointly controlled by said first and second mentioned members, a plurality of key code drums positionable to a variety of positions for controlling said second mentioned members, a plurality of pawls for advancing said code drums to said variety ofpositions, each of said pawls being designed to advance a corresponding one of said code drums, means for actuating said pawls, means for insuring the advancement of one of said code drums by the corresponding pawl upon actuation thereof during certain operating conditions, and means for enabling the advancement of more than one of said code drums by their corresponding pawls during actuation thereof under other operating conditions.

6. In a ciphering selector, a plurality of code combination controlled members, a like number of key code combination controlled members, an equal number of selectable elements jointly controlled by said first and second mentioned members, a plurality of key code drums positionable to a variety of positions for controlling said second mentioned members, a plurality of pawls for advancing said code drums to said variety of positions, each of said pawls being designed to advance a corresponding one of said code drums, means for actuating said pawls, a ratchet associated with each code drum for enabling the ad- 

